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- Subject: RE: ~= vs. !=
- From: virgil@... (Virgil Smith)
- Date: Wed, 26 Nov 2003 18:27:27 -0600
> Last time I checked, the "~" character was the standard
> logical symbol for "not." At least it was in my
> statistics class (e.g. "A|~B").
> Whereas with the "~=" operator, at least this would
> be familiar to people who took logic courses.
Fine, according to "Contemporary Logic Design, by Randy H. Katz, The
Benjamin Cummings/Publishing Company Inc., copyright 1994", page 19 under
"the complement (inversion, negation) of X as one of X',
X, !X, /X, or \X."
You will note that ! is in that list, but ~ is not (which honestly is an
oversight in this listing). However, I think the statement that '"~" is the
standard logic symbol "familiar to people who took logic courses"' is
incorrect through insufficient sampling.
Furthermore, I'm befuddled by the statement that != is a *special* case. My
personal frequent language switching is between C/C++ and Visual Basic which
is a continual flip between != and <>. What's more when switching languages
I personally consider the '=' character to be the first thing to watch out
for due to frequent switches between != and <>, = and ==, and from my
student Pascal/C days = and :=. The only strange thing about ~= IMO is that
I've never used a language that used that notation. Of course maybe I'm
just not specifically "script" language savvy enough for this crazy
discussion. We may as well be arguing about the 0 vs. 1 based array issue
or the use of ()'s for array access for all of the frequency of differences
So, does anyone have references for their assertions of the frequency of !=